Display device having sealing film

ABSTRACT

In order to provide a display device of high reliability in which an amount of moisture and oxygen, which are a factor for deteriorating a characteristics of a display device, entering from a sealing agent is reduced and its manufacturing method, the present invention has a sealing film. Accordingly, an interlayer insulating film including an organic material of the display device (panel) is no longer exposed to the atmosphere outside of the display device. Therefore, it becomes possible to prevent moisture and oxygen outside of the display device from entering inside of the display device through an insulating film and the like including a hygroscopic organic material. In addition, various degradations such as contamination of an inner part of the display device caused by moisture, oxygen and the like, the degradation of electric properties, a dark spot and shrink can be prevented, thus enhancing reliability of the display device.

FIELD OF THE INVENTION

The present invention relates to a display device including an elementwhich has a light-emitting material (hereinafter referred to aslight-emitting element) between electrodes (hereinafter referred to asdisplay device) and a manufacturing method thereof. More specifically,the present invention relates to a display device using a light-emittingmaterial in which EL (Electro Luminescence) can be obtained.

BACKGROUND OF THE INVENTION

Recently, progress has been made in the development of a display device(EL display device) employing a light-emitting element (hereinafterreferred to as EL element) which uses EL phenomenon of a light-emittingmaterial. An EL display device does not need a backlight unlike a liquidcrystal display because the light-emitting element itself has an abilityto emit light. In addition, an EL display device has the advantages ofwide viewing angle, high contrast, and so on.

It is said that an EL element emits light by releasing energy whenelectrons injected from a cathode and holes injected from an anode arerecombined at a luminescence center in an organic compound layer to forma molecular exciter and when the molecular exciter moves back to theground state by applying a voltage with interposing the organic compoundlayer between a pair of electrodes. Singlet excitation and tripletexcitation are known as an excitation state, and it is considered thatlight-emission can be obtained through both the excitation states.

Moreover, there are an inorganic light-emitting material and an organiclight-emitting material as a light-emitting material which is used foran EL element, and an organic light-emitting material that requires alow driving voltage attracts attention.

However, after driving a certain period of time, an organic EL elementusing an organic material for the EL element has a problem in thatlight-emitting characteristics such as luminance and luminanceuniformity degrade drastically compared to those at the beginning. Thelow reliability is the main factor for the limited practicalapplication.

Moisture and oxygen which enter the organic EL element from outside arecited as one of the factors for deteriorating the reliability.

In the EL display device (panel) using an EL element, the moisture whichenters an inner part leads a serious degradation in reliability to causea dark spot, shrink and a degradation of luminance from a peripheralpart of a light-emitting device. The dark spot is phenomenon in whichluminance decreases partially (including nonluminescent element), and itoccurs when a top electrode has a hole. In addition, the shrink isphenomenon in which luminance degrades from a pixel end part (edge).

The development has done on a display device having a structure whichprevents the above degradations of an EL element. There is a method forstoring an EL element in an airtight vessel to confine the EL elementwithin an enclosed space and further providing drying agent in theenclosed space with isolating from the EL element (for example, seePatent Reference 1).

(Patent Reference 1)

Japanese published unexamined application Hei 9-148066

In addition, there is a method for forming a sealing agent on aninsulator where an EL element is formed and filling an enclosed spacesurrounded by a cover agent and the sealing agent with filler includingresin and the like to be shut out from an outer part (for example, seePatent Reference 2).

(Patent Reference 2)

Japanese published unexamined application Hei 13-203076

According to the above patent references, a sealing agent is formed onan insulator where an EL element is formed thereon. Then, an enclosedspace is formed, which is surrounded by the sealing agent and a coveragent by using the sealing agent. This sealing step is conducted in aninert gas atmosphere; therefore, there is a minute amount of moistureand oxygen in an inner part of a display device in the immediateaftermath of the sealing, not a large amount of moisture and oxygen fromthe beginning.

That is, moisture that is to be a cause for a degradation such as a darkspot enters inside of a display device after sealing in many cases. Inaddition, an insulator and a cover agent are often metal or glass;therefore, moisture and oxygen enter from the sealing agent.

FIG. 1 is a top view of the EL display described in Patent Reference 2.Reference numeral 401 shown by a dotted line denotes a source sidedriving circuit; 402, a gate side driving circuit; 403, a pixel portion;and 409, an FPC (flexible print circuit). In addition, reference numeral404 denotes a cover agent; 405, a first sealing agent; and 406, a secondsealing agent. FIG. 27 is a cross-sectional view of a conventional ELdisplay device like that of FIG. 1 (the second sealing agent 406 is notshown). As shown in FIG. 27, in a region A of a sealing region, an ELelement is encapsulated in an inner portion by using a sealing agent.

According to Patent Reference 1 and Patent Reference 2 above, thesealing agent shuts the EL element off from external moisture like thismanner in the region A of the sealing region of FIG. 27.

In the case of the structure in which an EL element is stored in anairtight vessel as described in Patent Reference 1, an EL display devicegrows in size by the size of the vessel. Moreover, the drying agent isarranged separately from the EL element to prevent a negative effect bystacking a drying agent (protective layer including the drying agent)directly on the EL element. Accordingly, the airtight vessel growsfurther in size. Although the size of the EL display device increases,the size of a light-emitting portion does not change. Here, an advantageof a thin shape is not taken, which is needlessness of a backlight ofthe EL display device. Further, in the structure of Patent Reference 1,there is a risk that moisture which enters the airtight vessel comesinto contact with the EL element to lead a degradation of EL elementbecause the drying agent absorbs moisture in the airtight vessel.

In Patent Reference 2, a filler such as resin shuts an EL element offfrom external moisture. However, increase in the size of the EL displaydevice is inevitable because the sealing agent is applied to the regionA in FIG. 27 to fabricate an enclosed space.

As described above, the area of a part which dose not emit lightincreases when a display device area except a pixel portion emittinglight (region A in FIG. 27) is large. Accordingly, the increase in thesize of the display device is required in order to obtain the same sizeof light-emitting portion.

In order to solve this problem, a method for applying a sealing agentonto an insulating layer such as an interlayer film and a protectivefilm. FIG. 17 shows the EL display device above, and FIG. 2 shows anenclosed end part of a sealing region at an end. In FIG. 2, referencenumeral 21 denotes a substrate; 22, a counter substrate; 23, a gateinsulating film; 24 and 25, interlayer films; 26, a wiring; and 27, asealing agent.

As shown in FIG. 2, in the sealing region, the gate insulating film 23on the substrate 21, the interlayer films 24 and 25, and the wiring 26are sequentially stacked, and the sealing agent 27 is applied on theinsulating layer (laminated films). In this structure, it is possible toreduce the size of the region A in FIG. 27 which dose not emit light.FIG. 2 is an example; the materials of layers which are stacked on a TFTsubstrate side and the sequence of the laminated layer are not limitedto this example. Here, as an example, a display device has a structurein which a base film, a gate insulating film, a protective film, aninterlayer film and a wiring are sequentially stacked on a glasssubstrate and which has the wiring on the top of those films.

However, in the case where a sealing agent for sealing is on a laminatedfilms as shown in FIG. 2, all of the laminated films are exposeddirectly to the atmosphere outside of the panel. Accordingly, moistureand oxygen which are outside of the panel enter through the laminatedfilms into the display device. Further, in the case that a materialhaving high moisture permeability such as acrylic is used as theinterlayer film, the moisture and the oxygen which enter furtherincrease.

Moisture and oxygen enters from this acrylic serving as the interlayerfilm and top and bottom interfaces of the acrylic, and reach theinterlayer film adjoining to an EL element through a disconnecting partdue to inferior film formation of a source and drain electrodes in acontact hole. Accordingly, various degradations such as contamination ofthe inner part of the display device, a degradation of electricproperties, a dark spot and shrink are caused.

Therefore, an object of the present invention is to provide an ELdisplay device of high reliability and its manufacturing method bypreventing moisture and oxygen, the factors for degrading properties ofan EL element, from entering without increasing the size of the ELdisplay device.

SUMMARY OF THE INVENTION

In a sealing region at an end part of a display device, the presentinvention prevents contaminated materials such as moisture and oxygenoutside of a display device from entering an inner part of the displaydevice by shutting the inner part of the display device off from anouter part by using a film which forms the display device. In thepresent specification, a protective film which protects a light-emittingelement from contaminated materials by shutting the inner part of adisplay device off from the outer part is referred to as a sealing film.

A display device according to the present invention, comprising adisplay unit formed by arranging a light-emitting element using anorganic light-emitting material between a pair of substrates,

wherein the display unit is formed over an insulating layer formed oneither one of the substrate,

wherein the pair of substrates are formed outside of the display unit soas to surround a periphery of the display unit and are attached to eachother by a sealing agent formed on the insulating layer,

wherein at least one layer of the insulating layer is formed from anorganic resin material, and

wherein an outer end part of the insulating layer located outside of thesealing agent is covered with a sealing film.

A display device according to the present invention, comprising adisplay unit formed by arranging a light-emitting element using anorganic light-emitting material between a pair of substrates,

wherein the display unit is formed over an insulating layer formed oneither one of the substrate,

wherein the pair of substrates is formed outside of the display unit soas to surround a periphery of the display unit and are attached to eachother by a sealing agent formed on the insulating layer,

wherein at least one layer of the insulating layer is formed from anorganic resin material,

wherein the insulating layer have an opening to be covered with asealing film, and

wherein the sealing agent is formed adjoining to the sealing film.

A display device according to the present invention, comprising adisplay unit formed by arranging a light-emitting element using anorganic light-emitting material between a pair of substrates,

wherein the display unit is formed over an insulating layer formed oneither one of the substrate,

wherein the pair of substrates is formed outside of the display unit soas to surround a periphery of the display unit and are attached to eachother by a sealing agent formed on the insulating layer,

wherein at least one layer of the insulating layer is formed from anorganic resin material,

wherein the insulating layer have an opening to be covered with asealing film, and

wherein an outer end part of the insulating layer located outside of thesealing agent is covered with the sealing film.

A display device according to the present invention, comprising adisplay unit formed by arranging a light-emitting element using anorganic light-emitting material between a pair of substrates,

wherein the display unit is formed over an insulating layer formed oneither one of the substrate,

wherein the pair of substrates is formed outside of the display unit soas to surround a periphery of the display unit and are attached to eachother by a sealing agent formed on the insulating layer,

wherein at least one layer of the insulating layer is formed from anorganic resin material,

wherein the insulating layer has plural openings to be covered with asealing film, and

wherein the sealing agent is formed adjoining to the sealing film.

A display device according to the present invention, comprising adisplay unit formed by arranging a light-emitting element using anorganic light-emitting material between a pair of substrates,

wherein the display unit is formed over an insulating layer formed oneither one of the substrate,

wherein the pair of substrates is formed outside of the display unit soas to surround a periphery of the display unit and are attached to eachother by a sealing agent formed on the insulating layer,

wherein at least one layer of the insulating layer is formed from anorganic resin material,

wherein the insulating layer has plural openings to be covered with asealing film, and

wherein an outer end part of the insulating layer located outside of thesealing agent is covered with a sealing film.

According to the structures above, the insulating layer may have pluralopenings to be covered with a sealing film, the openings may be providedat any place in an inner part of the display device. The openings may besealed between a pixel portion and a peripheral driving circuit, andalso may be sealed in a sealing region. However, an outer end part ofthe insulating layer located outside of the sealing agent needs to becovered with a sealing film. Therefore, in the case where an opening islocated outside of a sealing agent, the outer end part may be an openingas shown in FIG. 4.

According to the structures above, a film including one or plural kindsof films selected from a conductive thin film and an insulating thinfilm may be used as the sealing film. As a conductive thin film, a filmincluding one or plural kinds of elements selected from Al, Ti, Mo, Wand Si may be used. As an insulating thin film, a film including one orplural kinds of films selected from a silicon nitride film, a siliconnitride oxide film or a nitrogen-containing carbon film may be used.

According to the structures above, a film including one or plural kindsof materials selected from the group consisting of acrylic, polyamideand polyimide can be used for the organic resin material. In addition,the organic resin material may be formed from a material in which askeletal structure is formed by bonding of silicon and oxygen. As thematerial in which a skeletal structure is formed due to bonding ofsilicon and oxygen, siloxanic polymer is cited as a typical example.Specifically, it is a material wherein a skeletal structure is formed bybonding of silicon and oxygen and wherein a substituent includes atleast hydrogen, or a material wherein a substituent includes at leastone from the group consisting of fluorine, alkyl and aromatichydrocarbon.

A method for manufacturing a display device according to the presentinvention, including a display unit formed by arranging a light-emittingelement using an organic light-emitting material between a pair ofsubstrates, comprising the steps of:

forming the display unit over an insulating layer formed on either oneof the substrate;

forming the pair of substrates outside of the display unit so as tosurround a periphery of the display unit to be attached to each other bya sealing agent formed on the insulating layer;

forming at least one layer of the insulating layer from an organic resinmaterial; and

covering an outer end part of the insulating layer located outside ofthe sealing agent with a sealing film.

A method for manufacturing a display device according to the presentinvention, including a display unit formed by arranging a light-emittingelement using an organic light-emitting material between a pair ofsubstrates, comprising the steps of:

forming the display unit over an insulating layer formed on either oneof the substrate;

forming the pair of substrates outside of the display unit so as tosurround a periphery of the display unit to be attached to each other bya sealing agent formed on the insulating layer;

forming at least one layer of the insulating layer from an organic resinmaterial;

forming an opening in the insulating layer to be covered with a sealingfilm; and

forming the sealing agent to be adjoining to the sealing film.

A method for manufacturing a display device according to the presentinvention, including a display unit formed by arranging a light-emittingelement using an organic light-emitting material between a pair ofsubstrates, comprising the steps of:

forming the display unit over an insulating layer formed on either oneof the substrate;

forming the pair of substrates outside of the display unit so as tosurround a periphery of the display unit to be attached to each other bya sealing agent formed on the insulating layer;

forming at least one layer of the insulating layer from an organic resinmaterial;

forming an opening in the insulating layer to be covered with a sealingfilm; and

covering an outer end part of the insulating layer located outside ofthe sealing agent with a sealing film.

A method for manufacturing a display device according to the presentinvention, including a display unit formed by arranging a light-emittingelement using an organic light-emitting material between a pair ofsubstrates, comprising the steps of:

forming the display unit over an insulating layer formed on either oneof the substrate;

forming the pair of substrates outside of the display unit so as tosurround a periphery of the display unit to be attached to each other bya sealing agent formed on the insulating layer;

forming at least one layer of the insulating layer from an organic resinmaterial;

forming plural openings on the insulating layer to be covered with asealing film respectively; and

forming the sealing agent to be adjoining to the sealing film.

A method for manufacturing a display device according to the presentinvention, including a display unit formed by arranging a light-emittingelement using an organic light-emitting material between a pair ofsubstrates, comprising the steps of:

forming the display unit over an insulating layer formed on either oneof the substrate;

forming the pair of substrates outside of the display unit so as tosurround a periphery of the display unit to be attached to each other bya sealing agent formed on the insulating layer;

forming at least one layer of the insulating layer from an organic resinmaterial;

forming plural openings in the insulating layer to be covered with asealing film respectively; and

covering an outer end part of the insulating layer located outside ofthe sealing agent with a sealing film.

According to the structures above, the insulating layer may have pluralopenings to be covered with a sealing film, and the openings may beprovided at any place in an inner part of a display device. The openingsmay be sealed between a pixel portion and a peripheral driving circuit,and also may be sealed in a sealing region. However, an outer end partof the insulating layer located outside of the sealing agent needs to becovered with a sealing film. Therefore, in the case where an opening islocated outside of a sealing agent, the outer end part may be an openingas shown in FIG. 4.

According to the structures above, the sealing film may be formed of oneor plural kinds of films selected from a conductive thin film and aninsulating thin film. A conductive thin film may be formed of one orplural kinds of elements selected from the group consisting of Al, Ti,Mo W and Si. An insulating thin film may be formed of one or pluralkinds of films selected from a silicon nitride film, a silicon nitrideoxide film or a nitrogen-containing carbon film.

According to the structures above, the organic resin material can beformed from one or plural kinds of materials selected from the groupconsisting of acrylic, polyamide and polyimide. In addition, the organicresin material may be formed from a material in which a skeletalstructure is formed by bonding of silicon and oxygen. As the material inwhich a skeletal structure is formed due to the bonding of silicon andoxygen, siloxanic polymer is cited as a typical example. Specifically,it is a material wherein a skeletal structure is formed due to thebonding of silicon and oxygen and wherein a substituent includes atleast hydrogen, or a material wherein a substituent includes at leastone from the group consisting of fluorine, alkyl and aromatichydrocarbon.

By providing a sealing film according to the present invention, aninterlayer insulating film including an organic material of the displaydevice (panel) is no longer exposed directly to the atmosphere outsideof the display device. Therefore, it becomes possible to preventmoisture and oxygen outside of the display device from entering aninside of the display device through an insulating film and the likeincluding a hygroscopic organic material. In addition, variousdegradations such as contamination of an inner part of the displaydevice caused by moisture and oxygen, the degradation of electricproperties, a dark spot and shrink can be prevented to enhancereliability of the display device. Moreover, a display device of highreliability can be manufactured without increasing manufacturing stepsbecause a film forming a display device is used as a sealing film(protective film) in the present invention.

EFFECT OF THE INVENTION

By adopting the structures of the present invention, the effect as shownbelow can be obtained.

By providing a sealing film, an interlayer insulating film including anorganic material of the display device (panel) is no longer exposeddirectly to the atmosphere outside of the display device. Therefore, itbecomes possible to prevent moisture and oxygen outside of the displaydevice from entering an inside of the display device through aninsulating film and the like including a hygroscopic organic material.Accordingly, various degradations such as contamination of an inner partof the display device caused by moisture and oxygen, the degradation ofelectric properties, a dark spot and shrink can be prevented to enhancereliability of the display device.

In addition, a display device of high reliability can be manufacturedwithout increasing manufacturing steps because a film made of the samematerial as that of a film forming the display device is formed at thesame time to be used for a sealing film.

A display device formed like above obtains sufficient operationproperties and reliability, because of having a structure in whichcontaminated materials are shut off in a sealing region in an end partof the display device. Accordingly, an electric appliance using adisplay device of the present invention also obtains high reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view showing a conventional display device;

FIG. 2 is a view showing a conventional structure;

FIG. 3 is a view showing a structure according to the present invention;

FIG. 4 is a view showing a structure according to the present invention;

FIGS. 5A–5B are views showing a structure of the present invention;

FIGS. 6A–6D are cross-sectional views showing the steps of manufacturingan active matrix substrate;

FIGS. 7A–7C are cross-sectional views showing the steps of manufacturingan active matrix substrate;

FIGS. 8A–8C are cross-sectional views showing the steps of manufacturingan active matrix substrate;

FIG. 9 is a cross-sectional view showing an active matrix substrate;

FIG. 10 is a cross-sectional view showing a display device of thepresent invention;

FIG. 11 is a cross-sectional view showing a display device of thepresent invention;

FIGS. 12A–12F are views showing examples of a display device;

FIGS. 13A–13D are views showing an example of a display device;

FIGS. 14A–14C are views showing an example of a display device;

FIG. 15 is a view showing a result of a reliability evaluation of aconventional display device;

FIG. 16 is a view showing a result of a reliability evaluation of adisplay device according to the present invention;

FIG. 17 is a cross-sectional view of a conventional EL display device;

FIG. 18 is a cross-sectional view of a display device according to thepresent invention;

FIG. 19 is a top view of a conventional display device;

FIG. 20 is a cross-sectional view of a display device according to thepresent invention;

FIG. 21 is a cross-sectional view of a display device according to thepresent invention;

FIG. 22 is a top view of a display device according to the presentinvention;

FIG. 23 is a view showing a result of a reliability evaluation of adisplay device according to the present invention;

FIG. 24 is a view showing a result of a reliability evaluation of adisplay device according to the present invention;

FIG. 25 is a view showing a result of a reliability evaluation of adisplay device according to the present invention;

FIG. 26 is a view showing a display device according to the presentinvention; and

FIG. 27 is a cross-sectional view showing a conventional EL displaydevice.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

(Embodiment Mode 1)

Referring to the figures, an embodiment mode of the present inventionwill be described in detail.

In a sealing region of a display device, a gate insulating film, aninterlayer film and a wiring, which are over a TFT substrate, arestacked to form an insulating layer. In FIG. 3, reference numeral 31denotes a substrate; 32, a counter substrate; 33, an insulating film; 34and 35 interlayer films; 36, a sealing film serving as a protectivefilm; 37, a sealing agent. The lamination in FIG. 3 is an example;materials of layers stacked on a TFT substrate side and a sequence ofthe lamination are not limited to this example. Here, as an example, adisplay device has a structure in which a base film (not shown in thefigure), a gate insulating film, a protective film, an interlayer filmand a sealing film are stacked on a glass substrate, having the sealingfilm on the top of those films.

As described above, to reduce the area of display device exceptnonluminescent pixel portion, the sealing agent is applied onto thelaminated insulating layer, attached to the substrate including theinsulating layer and to the counter substrate. As shown in FIG. 3, thepresent embodiment mode has a structure wherein the sealing film stackedon the top is formed from the same material as that of the wiring at thesame time, covering the base film (not shown in the figure), the gateinsulating film, the interlayer film, the protective film and so onwhich have been formed in advance.

By this sealing film, a film such as the interlayer film no longer isexposed to the atmosphere outside of the display device. Therefore, itbecomes possible to prevent moisture and oxygen outside of the displaydevice from entering the inner part of the display device through theinterspace between films. Accordingly, the reliability of the displaydevice can be enhanced by preventing various degradations caused bymoisture and oxygen such as contamination of an inner part of thedisplay device, the degradation of electric properties, a dark spot andshrink. Moreover, in the present invention, a display device with highreliability can be manufactured without increasing the manufacturingsteps because a film made of the same material as that of a film whichforms the display device is used for a sealing film.

The sealing film which shuts moisture and oxygen off serves as aprotective film, therefore, it is preferable that the sealing film has adense structure.

In addition, a film including one or plural kinds of films selected froma conductive thin film and an insulating thin film may be used as thesealing film. As a conductive thin film, a film including one elementselected from the group consisting of Al, Ti, Mo, W and Si, or an alloyfilm including the plural elements may be used. As an insulating thinfilm, a film including one or plural kinds of films selected from asilicon nitride film, a silicon nitride oxide film or anitrogen-containing carbon film can be used.

In addition, acrylic, polyamide, polyimide and the like can be used foran organic resin material employed for the insulating film, and theorganic resin material is not limited to these materials. Further, amaterial wherein a skeletal structure is formed by bonding of siliconand oxygen can be used for the organic resin material. As the materialin which a skeletal structure is formed due to the bonding of siliconand oxygen, siloxanic polymer is cited as a typical example.Specifically, a material is cited, wherein a skeletal structure isformed due to the bonding of silicon and oxygen and wherein asubstituent includes at least hydrogen, or a material wherein asubstituent includes at least or one of the group consisting offluorine, alkyl and aromatic hydrocarbon.

Further, as shown in FIGS. 5, two or more layers of sealing film as wellas single layer of the sealing film may be provided. In the case ofcovering with a conductive film, as shown in FIG. 5(B), the conductivefilm is required to be stacked only in a sealing region being separatedfrom an inner region of the display device in order to prevent shortcircuit and the like in an inner part of the display device. Theblocking effect is further improved when the sealing film is stacked inan end part of the display device to shut off like this manner, comparedto that of the case of using a single layer sealing film.

As shown in a side view of FIG. 3, a film in a lower layer to be coveredis preferred to make an inclined plane have a form with a curvatureradius varying continuously (smooth) in the case of covering with asealing film, because a thin film in an upper layer is formedcontinuously. In the case where the surface of the inclined plane of afilm in the lower layer is not smooth, the sealing film reduces itsthickness on the surface of the film in the lower layer to be broken.The broken film cannot block contaminated materials sufficiently,thereby making the present invention less effective. In addition, whenthe surface of the lower layer film to be covered is smooth, the goodcoverage of the sealing film to be formed thereon is obtained.Consequently, the effectiveness of the present invention is improved.Therefore, it is preferable to conduct wet etching by using aphotosensitive material as a lower layer film, because of the decreasein rough parts on a film surface and the improve in surface smoothness.

As described above, a display device with high reliability, can beobtained which blocking contaminated materials which becomes a factorfor a degradation without increasing a display device area except anonluminant pixel portion.

(Embodiment Mode 2)

An embodiment mode of the present invention is described in detail withreference to the figures.

In a sealing region of a display device, an insulating film, aninterlayer film and a wiring over a TFT substrate are stacked to form aninsulating layer. In FIG. 4, reference numeral 41 denotes a substrate;42, a counter substrate; 43, an insulating film; 44 and 45, interlayerfilms; 46, a sealing film which serves as a protective film; 47, asealing agent. The lamination in FIG. 4 is an example; materials of afilm stacked on a TFT substrate side and a sequence of the laminationare not limited to this example. Here, as an example, a display devicehas a structure in which an base film (not shown in the figure), aninsulating film, a protective film, and an interlayer film are stackedon a glass substrate, having the sealing film on the top of those films.

As described before, a sealing agent is applied onto the laminatedinsulating layer and attaches the substrate including the insulatinglayer to the counter substrate in order to reduce the area of a panelarea except a pixel portion. As shown in FIG. 4, the present embodimentmode has a structure wherein openings are provided in an insulatingsubstrate, an inter layer film, a protective film and the like, formingthe sealing film at the opening so as to cover the laminated films. Thissealing film is formed from the same material as that of the wiring atthe same time with the formation of the wiring.

By this sealing film, the insulating layer including an organic resinmaterial and the like below the sealing film is divided into an innerside region and an outer side region in the display device. Those filmsin an inner side region of the display device are not exposed directlyto the atmosphere outside of display device. Therefore, moisture andoxygen outside of the display device are blocked by the sealing film andcannot enter the inside of the display device even in the case where theinsulating layer in the outer region of the display device is exposed tothe atmosphere, and where the moisture and oxygen outside of the displaydevice go through the interlayer film and interspace between the filmsto enter the panel. Therefore, it is possible to prevent variousdegradations which are caused by moisture and oxygen such ascontamination of an inner part of the display device, the degradation ofelectric properties, a dark spot and shrink. Accordingly, reliability ofthe display device can be improved. In addition, reliability of thedisplay device to be manufactured can be improved without increasingmanufacturing steps because the sealing film is formed from the samematerial as that of the film which forms the display device at the sametime.

The sealing film which blocks moisture and oxygen serves as a protectivefilm, therefore, it is preferable that the sealing film has a densestructure.

In addition, a film including one or plural kinds of films selected froma conductive thin film and an insulating thin film may be used as thesealing film. As the conductive thin film, a film such as a filmincluding one element or alloy film including plural elements selectedfrom the group consisting of Al, Ti, Mo, W and Si may be used. As theinsulating thin film, a film including one or plural kinds of filmsselected from a silicon nitride film, a silicon nitride oxide film or anitrogen-containing carbon film can be used.

Moreover, acrylic, polyamide and polyimide can be used for the organicresin material used for the insulating layer, and the organic resinmaterial is not limited to these materials. In addition, the organicresin material may be formed from a material in which a skeletalstructure is formed by bonding of silicon and oxygen. As the material inwhich a skeletal structure is formed due to the bonding of silicon andoxygen, siloxanic polymer is cited as a typical example. Specifically, amaterial wherein a skeletal structure is formed due to the bonding ofsilicon and oxygen and wherein a substituent includes at least hydrogen,or a material wherein a substituent includes at least one from a groupconsisting of fluorine, alkyl and aromatic hydrocarbon.

In addition, a structure in which a sealing film may divide a multilayerfilm in the inner part of the display device, and a structure in whichthe sealing film covers an end part of the panel as described inEmbodiment Mode 1 are acceptable. The multilayer film may be dividedplural times and at any place in an inner part of the display device.Therefore, the multilayer film may be divided between a pixel region anda peripheral driving circuit region, and it may be divided in a sealingregion.

The insulating layer may be provided with plural openings to be coveredwith a sealing film, and the openings may be provided at any place inthe inner part of the display device. The openings may be sealed betweenthe pixel region and the peripheral driving circuit region, and also maybe sealed in the sealing region. However, an external end part of theinsulating layer that is located outside of the sealing agent needs tobe covered with the sealing film. Accordingly, in the case where theopening is located outside of a sealing agent, the external end part maybe the opening as shown in FIG. 4.

Further, in FIG. 4 of the present embodiment mode, the opening is formedso as to reach a glass substrate; however the structure of the presentinvention is not limited to that. That is, it is enough if theinsulating film including a hygroscopic organic material is covered witha sealing film. Therefore, the openings may be formed to reach a filmwhich is usable as a sealing film such as a silicon nitride film and theopenings may be covered with the sealing film.

In addition, as shown in FIGS. 5, two or more layers of sealing film aswell as one layer of the sealing film may be formed. In FIG. 5(A),reference numeral 501 denotes a substrate; 502, a counter substrate;503, insulating films; 504 and 505, interlayer films; 506 and 508,sealing films serving as a protective film; and 507, a sealing agent. Inthis case, in order to prevent short circuit and the like occurringinside of the display device, a sealing film is formed apart from theinner region of the display device to be stacked on a sealing regionalone as shown in FIG. 5(B) when a conductive film is used for thesealing film. In FIG. 5(B), reference numeral 511 denotes a substrate;512, a counter substrate; 513, an insulating film; 514 and 515,interlayer films; 516 and 518, sealing films serving as a protectivefilm; and 517, a sealing agent. Like this manner, the contaminatedmaterials are blocked by increasing the number of dividing in an innerpart of the display device, being combined with the structure coveringan end part, and stacking films at the end part of the display device.Accordingly, the blocking effect on contaminated materials is furtherimproved compared to the case of using the single layer of the sealingfilm.

The present embodiment mode can be combined with Embodiment Mode 1freely.

As described above, a display device with high reliability which blockscontaminated materials such as moisture and oxygen to be a factor fordegradation without increasing an area of the display device except anonluminescent pixel portion.

(Embodiment)

[Embodiment 1]

The present embodiment describes a method for manufacturing an activematrix substrate with reference to FIGS. 6 to 9. Although an activematrix substrate has plural TFTs, the method for manufacturing theactive matrix substrate is described by using a case of having a drivingcircuit portion including an n-type channel TFT and a p-type TFT, andhaving a pixel portion.

As a base film 300, a silicon nitride oxide film is formed on asubstrate 200 having an insulating surface in a thickness of 10 to 200nm (preferably 50 to 100 nm) by a plasma CVD method. A hydrogenatedsilicon nitride oxide film is then stacked thereon in a thickness of 50to 200 nm (preferably 100 to 150 nm). In the present embodiment, a50-nm-thick silicon nitride oxide film and a 100-nm-thick hydrogenatedsilicon nitride film are formed by a plasma CVD method. As the substrate200, a glass substrate, a quartz substrate, a silicon substrate, a metalsubstrate or stainless substrate having an insulating film on itssubstrate may be used. In addition, a plastic substrate having a heatresistance may be used, which enables to resist a processing temperatureof the present embodiment. Moreover, a flexible substrate may be usedfor the substrate 200. Further, a double layer structure and a structurewhere single layer or two or more layers of the undercoat (insulating)films are stacked may be used as the base film.

Next, a semiconductor film 301 is formed on a base film (FIG. 6(A)). Asemiconductor film may be formed in a thickness of 25 to 200 nm(preferably 30 to 150 nm) by well-known means (sputtering method, LPCVDmethod, plasma CVD method or the like). Although materials of thesemiconductor film is not limited, the semiconductor film is preferablyformed from silicon, a germanium-silicon (SiGe) alloy or the like. Theamorphous silicon film is processed by a thermal crystallization methodand a laser crystallization method using a metal element which promotescrystallization.

In the present embodiment, an amorphous silicon film is formed in athickness of 54 nm by a plasma CVD method as the semiconductor film.Nickel is used as a metal element and introduced onto the amorphoussilicon film by a solution application method. As for the method forintroducing a metal element to an amorphous silicon film, there is noparticular limitation as long as it is a method by which the metalelement exists on the surface or inside of the amorphous silicon film.For example, a sputtering method, a CVD method, a plasma processingmethod (including a plasma CVD method), an absorption method and amethod for applying a metal salt solution may be used. Among these, themethod using a solution is simple and convenient, and it is useful inthat control on a concentration of a metal element is easy. In addition,in order to improve surface wettability and to spread a solution over anentire surface of the amorphous silicon film, it is preferable to forman oxide film by UV light irradiation under oxygen atmosphere, a thermaloxidization method and a processing by ozone moisture including hydroxyradical, hydrogen peroxide solution or the like.

A thermal treatment is conducted at a temperature from 500 to 550° C.,for 8 to 20 hours, to crystallize the amorphous silicon film. In thepresent embodiment, nickel is used as the metal element, and ametal-containing layer 302 is formed to introduce the metal element ontothe amorphous silicon film 301. Four-hour-thermal treatment is thenconducted at 550° C. to obtain a first crystalline silicon 303 (FIGS.6(B) and 6(C)).

Next, the first crystalline silicon film 303 is irradiated by a laserbeam to induce crystallization, and a second crystalline silicon film304 is obtained. The semiconductor film is irradiated by a laser beam bya laser crystallization method. The laser to be used is preferably asolid-state laser, a gas laser and a metal laser of a continuousoscillation type. As the solid-state laser, there are a YAG laser, aYVO₄, a YLF laser, a YAlO₃ laser, a glass laser, a ruby laser, analexandrite laser, Ti: sapphire laser and the like of a continuousoscillation type. As the gas laser, there are an Ar laser, a Kr laser, aCO₂ laser and the like of a continuous oscillation type. As the metallaser, a helium-cadmium laser, a cupper vapor laser and a metal vaporlaser of a continuous oscillation type are cited. Moreover, an excimerlaser of continuous emission type can be adopted. The laser beam may beconverted to a higher harmonic wave by a nonlinear optical element.Excellent conversion efficiency is obtained when crystals called LBO,BBO, KDP, KTP, KB5 and CLBO are used for the nonlinear optical element,for example. Conversion efficiency can be increased drastically byputting these nonlinear optical elements into a laser oscillator. Thelaser of a higher harmonic wave is generally doped with Nd, Yb, Cr andthe like. The excitation of Nd, Yb, Cr and the like induce laseroscillation. An operator may select appropriate types of dopant. As thesemiconductor film, an amorphous semiconductor film, a microcrystalsemiconductor film, a crystalline semiconductor film and the like arecited, and a compound semiconductor film having an amorphous structuresuch as an amorphous silicon germanium film and an amorphous siliconcarbide film may be applied.

Thus obtained crystalline semiconductor film 304 is patterned by aphotolithography method to form semiconductor layers 305 to 308.

In addition, after forming the semiconductor layers 305 to 308, a minuteamount of impurity element (boron or phosphorus) may be doped in orderto control a threshold value of a TFT.

Next, a gate insulating film 309 covering the semiconductor layers 305to 308 is formed. The gate insulating film 309 is formed of aninsulating film including silicon by a plasma CVD method or a sputteringmethod. At this time, the thickness of the gate insulating film 309 isset to be 40 to 150 nm. In the present embodiment, a 115-nm-thicksilicon nitride oxide film is formed by a plasma CVD method. Of course,the gate insulating film is not limited to a silicon nitride oxide film,therefore, another insulating film of single layer structure or a doublelayer structure may be used.

Next, a first conductive film of 20 to 100 nm film thickness and asecond conductive film of 100 to 400 nm film thickness are stacked to beformed on the gate insulating film. The first conductive film and thesecond conductive film may be formed from an element selected from thegroup consisting of Ta, W, Ti, Mo, Al and Cu, an alloy material or acompound material including the elements as a major component. Moreover,as the first conductive film and the second conductive film, asemiconductor represented by polycrystalline silicon film doped withimpurity element such as phosphorus and AgPdCu alloy may be used. Notlimited to the film having a double layer structure, a triple layerstructure may be employed, in which a 50-nm-thick tungsten film, a500-nm-thick alloy film of aluminum and silicon (Al—Si) and a30-nm-thick titanium nitride film are stacked sequentially for example.In the case of using the triple layer structure, tungsten nitride may beused instead of tungsten of the first conductive film, and an alloy filmof aluminum and titanium (Al—Ti) may be used instead of the alloy filmof the aluminum and silicon (Al—Si) in the second conductive film. Inaddition, a titanium film may be used instead of the titanium nitridefilm in the third conductive film. Also, a single layer structure may beused. In this embodiment, a 30-nm-thick tantalum nitride film 310 and370-nm-thick tungsten film 311 are formed in sequential lamination onthe gate insulating film 309 (FIG. 7(A)).

Next, masks 312 to 316 made of resist are formed by using aphotolithography method to conduct a first etching treatment in order toform an electrode and a wiring. Using an ICP (Inductively CoupledPlasma) etching method, etching conditions (electric energy to beapplied to a coil shaped electrode, electric energy to be applied to asubstrate side electrode, a temperature of the electrode on a substrateside and the like) is properly controlled. Accordingly, the firstconductive film and the second conductive film can be etched into adesired tapered shape. As an gas used for etching, a chlorine gastypified by Cl₂, BCl₃, SiCl₄, CCl₄ and the like, a fluorine gas typifiedby CF₄, SF₆, NF₃ and the like, and O₂ can be suitably used.

By the first etching treatment, conductive layers 317 to 321 of a firstshape made of the first conductive layer and the second conductive layer(first conductive layers 317 a to 321 a and second conductive layers 317b to 321 b) are formed (FIG. 7(B)).

Next, a second etching treatment is conducted without removing a maskmade of resist. Here, a W film is etched selectively. The secondconductive layers 322 b to 326 b are formed by the second etchingtreatment at this time. On the other hand, the first conductive layers322 a to 326 a are hardly etched to form the conductive layers 322 to326 of a second shape.

A first doping treatment is then conducted without removing a mask madeof resist to add a low-concentration impurity element which imparts ann-type to a semiconductor layer. The doping treatment may be conductedby an ion doping method or an ion implantation method. As an impurityelement imparting an n-type, a Group 15 element such as phosphorus (P)or arsenic (As) are typically used, but phosphorus (P) is used at thistime. In this case, the conductive layers 322 to 326 serve as a maskwith respect to impurities imparting an n-type, and impurity regions 327to 330 are formed in a self-aligning manner. An impurity elementimparting an n-type is doped into the impurity regions 327 to 330 in aconcentration of from 1×10¹⁸ to 1×10²⁰/cm³ (FIG. 7(C)).

After removing the mask made of resist, masks 331 a to 331 c made ofresist are newly formed to conduct a second doping treatment at a higheraccelerating voltage than that of the first doping treatment. The dopingtreatment is conducted so as to add an impurity element to a lowersemiconductor layer in the tapered part of the first conductive layer,by using the second conductive layers 323 b and 326 b as a mask withrespect to the impurity element. A third doping treatment is thenconducted to obtain a state of FIG. 8(A) at a lower accelerating voltagethan that of the second doping treatment. By the second and the thirddoping treatments, an impurity element imparting an n-type is doped withlow-concentration impurity regions 335 and 341 which overlaps with thefirst conductive layer in a concentration of from 1×10¹⁸ to 5×10¹⁹/cm³,and an impurity element imparting an n-type is doped withhigh-concentration impurity regions 334, 337 and 340 in a concentrationof from 1×10¹⁹ to 5×10²¹/cm³.

As a matter of fact, by setting a proper accelerating voltage, alow-concentration impurity region and a high-concentration impurityregion can be formed by one time of doping treatment of the second andthird doping treatment.

Next, after removing a mask made of resist, masks 342 a and 342 b madeof resist are newly formed to conduct a fourth doping treatment. By thefourth doping treatment, impurity regions 343, 344, 347 and 348 areformed in which an impurity element imparting a conductivity type whichis opposite to that of the first conductivity type is doped with asemiconductor layer to be served as an active layer of a p-channel typeTFT. By using the first conductive layer and the second conductive layer322 and 326 are used as a mask with respect to an impurity element, animpurity element imparting a p-type is doped to form an impurity regionin a self-aligning manner. In the present embodiment, the impurityregions 343, 344, 347 and 348 are formed by an ion doping method usingdiborane (B₂H₆)(FIG. 8(B)). In the fourth doping treatment, asemiconductor layer forming an n-channel type TFT is covered with themasks 342 a and 342 b made of resist. By the first to third dopingtreatments, phosphorus is doped into impurity regions 332, 340 and 341in different concentrations respectively. By conducting doping treatmentso as that the concentration of the impurity element imparting a p-typeis from 1×10¹⁹ to 5×10²¹ atoms/cm³ in each of the regions, there arisesno problem because the impurity regions serves as a source and drainregion of a p-channel type TFF.

By the above-mentioned steps, an impurity region is formed in each ofthe semiconductor films.

Next, the masks 342 a and 342 b made of resist are removed to form afirst interlayer insulating film 349. The first interlayer insulatingfilm 349 is formed of an insulating film which includes silicon in athickness of 100 to 200 nm by using a plasma CVD method or a sputteringmethod (FIG. 8(C)). In the present embodiment, silicon nitride oxidefilm in a film thickness of 150 nm is formed by a plasma CVD method. Ofcourse, the first interlayer insulating film 349 is not limited to asilicon nitride oxide film, and an insulating film including differentsilicon of a single layer structure or a double layer structure may beemployed.

Next, in order to activate the impurity elements, a heat treatment,intense-light irradiation, or laser beam irradiation is conducted.Besides the activation, it is possible to recover plasma damage to agate insulating film and plasma damage to an interface between the gateinsulating and a semiconductor layer at the same time.

A second interlayer insulating film 350 including an inorganicinsulating film material or an organic insulator film material is formedon the first interlayer insulating film 349. A 1.6-μm-thick acrylicresin film is formed in the present embodiment, and the acrylic resinfilm with viscosity of 10 to 1000 cp, preferably 40 to 200 cp is used.In addition, a material in which a skeletal structure is formed bybonding of silicon and oxygen may be used. As the material in which askeletal structure is formed by bonding of silicon and oxygen, siloxanicpolymer is cited as a typical example. Specifically, a material whereina skeletal structure is formed due to the bonding of silicon and oxygenand wherein a substituent includes at least hydrogen, or a materialwherein a substituent includes at least one from the group consisting offluorine, alkyl and aromatic hydrocarbon. On the second interlayerinsulating film 350, a passivation film 351 including the nitrideinsulating film (typically, a silicon nitride film, silicon nitrideoxide film and nitride containing carbon film (CN)) is formed.

A metal film is then formed to be etched, and a source and drainelectrodes and respective wirings (not shown in the figures) which areelectrically connected to each of the impurity regions are formed. Forthe metal film, a film including an element such as aluminum (Al),titanium (Ti), molybdenum (Mo), tungsten (W) or silicon (Si), or analloy film using these elements may be employed. In the presentembodiment, a titanium film, an alloy film of titanium and aluminum anda titanium film (Ti, Al—Si and Ti) are stacked to have a thickness of100, 350 and 100 nm respectively, after that, those films are patternedand etched to form source electrode and drain electrodes 352 and each ofthe wirings (not shown in the figures). Accordingly, a p-channel typeTFT 11 and an n-channel type TFT 12 are formed in peripheral circuitportion 1, and an n-channel type TFT 13 and a p-channel type TFT 14 areformed in a pixel portion 2.

According to the present invention, the wiring may be formed so as tocover up a film in a lower layer at an end part of the substrate thatserves as a sealing region. When the wiring is formed, a film includingthe same material as that of the wiring is used as a sealing film. It isenough if the light-emitting element is not exposed to the externalatmosphere. Therefore, Embodiment Mode 1, Embodiment Mode 2, orcombination of those may be used for sealing the end part.

By this sealing film, the insulating layer such as the interlayer filmno longer is exposed to the atmosphere outside of the display.Therefore, it becomes possible to prevent moisture and oxygen outside ofthe display device from entering the inner part of the display devicethrough the insulating layer and interspace between films. Accordingly,the reliability of the display device can be enhanced by preventingvarious degradations caused by moisture and oxygen such as contaminationof an inner part of the display device, the degradation of electricproperties, a dark spot and shrink. Moreover, in the present invention,a display device with high reliability can be manufactured withoutincreasing the manufacturing steps because a film using the samematerial as that of a film which forms the display device is used for asealing film.

An electrode (an anode or a cathode in the case of an EL display device,or a pixel electrode in the case of a liquid crystal display device) isthen formed. Transparent conductive films such as ITSO, ITO, SnO₂including indium tin oxide and silicon oxide can be used for theelectrode, and a metal film such as Al can be used in the case of areflective liquid crystal display device. In the present embodiment, anelectrode 353 is formed by forming ITO to be etched into a desired shape(FIG. 9).

By the steps above, an active matrix substrate having a TFT iscompleted.

The present invention is not limited to the method for forming a TFT oftop-gate type (planer type) shown in the present embodiment. The presentinvention can be applied to a bottom-gate type (inversely staggeredtype), a dual-gate type having two gate electrodes arranged above andbelow of a channel region with two gate insulating films interposedtherebetween, and other structures.

[Embodiment 2]

The present embodiment describes an example of a method formanufacturing a display device by using a method for manufacturing aTFT, which is shown in Embodiment 1, when an active matrix substrate isformed. In the present specification, a display device refersgenerically to a display panel in which a light-emitting element formedon a substrate is sealed between the substrate and a cover agent, and adisplay module in which a TFT is incorporated in the display panel. Thelight-emitting element includes a layer having an organic compound(light-emitting layer) from which luminescence (Electro Luminescence)can be obtained by applying an electric field, an anode layer and acathode layer. In addition, as for the luminescence of an organiccompound, there are light-emission (fluorescence) which occurs when theorganic compound returns to a ground state from a singlet excitationstate, and light-emission (phosphorescence) which occurs when theorganic compound returns to a ground state from a triplet excitationstate. An EL material applicable for the present invention includes alllight-emitting materials emitting a light through the singlet excitationand the triplet excitation and the both the types of excitation.

In the present specification, all the layers formed between an anode anda cathode in a light-emitting element is defined as an organiclight-emitting layer. Specifically, the organic light-emitting layerincludes a light-emitting layer, a hole-injection layer, anelectron-injection layer, a hole-transport layer, an electron-transportlayer and the like. In general, a light-emitting element has a structurein which an anode layer, a light-emitting layer and a cathode layer arestacked sequentially. Besides this structure, the light-emitting elementhas a structure in which an anode layer, a hole-injection layer, alight-emitting layer, a cathode layer and the like are stackedsequentially, and a structure in which an anode layer, a hole-injectionlayer, a light-emitting layer, an electron-transport layer, an cathodelayer and the like are stacked sequentially in some cases.

FIG. 11 is a cross-sectional view of a display device of the presentembodiment. In FIG. 11, a p-channel type TFT 6003 and an n-channel typeTFT 6004 are formed in a peripheral circuit portion 6001, and ann-channel type TFT 6005 and a p-type channel TFT 6006 are formed in apixel region 6002, which are encapsulated in a sealing region 6000.Although the present embodiment may employ a double gate structure inwhich two channel-forming regions are formed, a single gate structure inwhich a single channel-forming region is formed and a triple gatestructure in which three channel-forming regions are formed may be used.

A driving circuit provided on a substrate 700 is formed by using a CMOScircuit in FIG. 9. Accordingly, it is possible to use the description onthe n-channel type TFT 11 and the p-channel type TF12 as a reference.Although a single gate structure is used in the present embodiment, adouble gate structure or a triple gate structure may be used.

Moreover, reference numeral 711 denotes a pixel electrode (an anode of alight-emitting element) including a transparent conductive film. As thetransparent conductive film, a compound of indium oxide and tin oxide, acompound of indium oxide and zinc oxide, a zinc oxide, a tin oxide andan indium oxide can be used. Further, a film formed by adding gallium tothe transparent conductive film. The pixel electrode 711 may be formedon a flat interlayer insulating film before forming the wiring. It iseffective to flatten steps due to a TFT by using a leveling filmincluding a resin. Insufficient emitting due to the steps is likely tooccur because a light-emitting layer formed later is very thin.Therefore, it is preferable to form the leveling film before forming thepixel electrode in order to form a light-emitting layer on a flat planeas far as possible.

After forming a wiring 701, a bank 712 is formed as shown in FIG. 11.The bank 712 may be formed by patterning an insulating film or anorganic resin film which have 100 to 400-nm-thick silicon. In addition,a material in which a skeletal structure is formed by bonding of siliconand oxygen may be used. As the material in which the skeletal structureis formed by bonding of silicon and oxygen, siloxanic polymer is citedas a typical example. Specifically, the material wherein the skeletalstructure is formed due to the bonding of silicon and oxygen and whereina substituent includes at least hydrogen, or a material wherein asubstituent includes at least one from the group consisting of fluorine,alkyl and aromatic hydrocarbon.

The bank 712 is an insulating film; therefore, damage by electro-staticdischarge in film formation needs attention. In the present embodiment,carbon particles and metallic particles are added to reduce electricresistivity, and static electricity is prevented from occuring. At thistime, the amount of the carbon particles and the metallic particles tobe added are controlled so as that the value of the electric resistivityis 1×10⁶ to 1×10¹² Ωm (preferably 1×10⁸ to 1×10¹⁰ Ωm).

On the pixel electrode 711, a light-emitting layer 713 is formed.Although only one pixel is shown in FIG. 11, light-emitting layersresponding to each color of R (red), G (green) and B (blue) is formedrespectively. In addition, a low-molecular weight organic light-emittingmaterial is formed by an evaporation method in the present embodiment.Specifically, laminated structure in which a 200-nm-thick copperphthalocyanine (CuPc) film is provided as a hole-injection layer, and a700-nm-thick tris-8-quinolinolato aluminum complex (Alq₃) film is formedthereon as a light-emitting layer, is formed. A color of light-emissioncan be controlled by adding fluorescent dye such as quinacridon,perylene or DCMl to Alq₃.

However, the example above is an example of an organic light-emittingmaterial that can be used as a light-emitting layer, there is no need tolimit the organic light-emitting material to the above mentionedexample. The light-emitting layer (layer emitting light to transfercarriers for the light-emission) may be formed by combining thelight-emitting layer, a charge-transporting layer or a charge-injectinglayer freely. For example, the present embodiment shows the example thatthe low-molecular weight organic light-emitting material is used as thelight-emitting layer. However, an intermediate-molecular weight organiclight-emitting material and a high-molecular weight organiclight-emitting material may be used. In the present specification, anorganic material having no sublimability in which a number of moleculesis no more than 20, or a length of molecular chains is no more than 10μm is defined as an intermediate-molecular weight organic light-emittingmaterial. Moreover, as an example of using a high-molecular weightorganic light-emitting material, a laminated structure in which20-nm-thick polythiophene (PEDOT) is provided as a hole-injecting layerby a spinning coating method and a 100-nm-thick polyparaphenylenevinylene (PPV) is provided thereon as a light-emitting layer may beused. In addition, when π-conjugated polymer of PPV is used, an emissionwavelength can be selected from red color to blue color. Further, aninorganic material such as silicon carbide can be used as acharge-transporting layer and a charge-injecting layer. A well-knownmaterial can be used for these organic light-emitting material andinorganic material.

A cathode 714 made of a conductive film is then provided on thelight-emitting layer 713. In the present embodiment, an alloy ofaluminum and lithium is used as the conductive film. Of course awell-known MgAg film (an alloy film of magnesium and silver) may beused. As a cathode material, a conductive film including a Group 1element or Group 2 element of the periodic table, or a conductive filmin which those elements are added may be used.

When the cathode 714 is formed, a light-emitting element is completed.The light-emitting element 715 denotes a diode formed of the pixelelectrode (anode) 711, the light-emitting layer 713 and the cathode 714.

It is effective to form a passivation film so as to cover thelight-emitting element 715 completely (not shown in the figures). Thepassivation film is formed of an insulating film including a carbonfilm, a silicon nitride film, a nitrogen-containing carbon film (CN) ora silicon nitride oxide film. A single layer of the insulating film orthe laminated layer of the combination of the insulating film is used asthe passivation film.

At this time, it is preferable to use a film with good coverage as apassivation film, therefore, using a carbon film and particularly a DLCfilm are effective. The DLC film can be formed at a temperature from aroom temperature to 100° C. or lower. Accordingly, the DLC film can beeasily formed above the light-emitting layer 713 having inferior heatresistance. In addition, the DLC film has a high blocking effect,enabling a control on an oxidization of the light-emitting layer 713.Therefore, it is possible to prevent a problem such that thelight-emitting layer 713 is oxidized while carrying out a sealing stepafterward.

Moreover, a sealing agent 717 is formed on the passivation film, and acover agent 720 is attached thereto. An ultraviolet curing resin may beused for the sealing agent 717, and it is effective to provide ahygroscopic material or an antioxidant material in an inner part.Furthermore, in the present embodiment, a glass substrate, a quartzsubstrate, a plastic substrate (including a plastic film) and a flexiblesubstrate having a carbon film (preferably) on both sides are used.Except for the carbon film, an aluminum film (AlON, AlN, AlO and thelike) and SiN can be used.

As described above, a display device having a structure shown in FIG. 11is obtained. In addition, it is effective to conduct the stepscontinuously up to forming the passivation film (not shown in thefigure) by using a film formation device of a multi-chamber system (orin-line system) without being exposed to the atmosphere. In addition, bydeveloping the above further, it is possible to conduct continuously upto the step attaching the cover agent 720 without being exposed to theatmosphere.

Further, it is possible to form an n-channel type TFT of high resistantagainst the degradation due to a hot carrier by providing an impurityregion overlapping with the gate electrode through an insulating film.Accordingly, a display device having high reliability can be realized.

Furthermore, the structure only of the pixel portion and the drivingcircuit is described in the present embodiment. However, by followingthe manufacturing steps of the present embodiment, a logic circuit suchas a signal separation circuit, a D/A converter, an operation amplifierand a γ correction circuit can be formed on the same insulator. A memoryand a microprocessor can be formed further.

In the present embodiment, in forming a wiring, a sealing film 718 isformed using the same material as that of the wiring at an end part of asubstrate serving as a sealing region according to the presentinvention. The sealing film is formed so as to cover up (coat) a film ina lower layer. It is enough if the insulating layer, particularly aninsulating film including a hygroscopic organic material is not exposedto the external atmosphere. Therefore, Embodiment Mode 1, EmbodimentMode 2, or the combination of those may be used for coating the end partand blocking, and the coating and the blocking are not limited to astructure in FIG. 11. Accordingly, the end part of the panel may becovered with the pixel electrode, the bank, the passivation film, thecathode and the like in a layer above the wiring. In the case ofcovering two or more layers, any combination of the films above may alsobe used.

In addition, as shown in FIG. 4, a structure in which a sealing film isformed at opening to divide a film of a lower layer into an inner sideregion and an outer region in a display device and prevent contaminatedmaterials from entering may also be used. FIG. 20 shows a structure inwhich a bare part of the insulating layer at the end part of the displaydevice is covered with the sealing film formed from the same material asthat of the wiring at the same time and in which the opening formed inthe insulating layer is covered with the sealing film. In FIG. 20,reference numeral 9000 denotes a sealing region; 9001, a peripheralcircuit portion; 9002, a pixel portion; 9003 and 9006, p-channel typeTFTs; 9004 and 9005, n-channel type TFTs; 2000, a substrate; 2001, awiring; 2011 and 2014, electrodes (anode or cathode); 2012, a bank;2013, a light-emitting layer; 2015, a light-emitting element; 2018, anopening; 2019, a sealing film (protective film) covering the opening2018 and side edge part; and 2017, a sealing agent. In the case ofcovering with a conductive film, the conductive film is formed apartfrom the inner region of the display device to be stacked on the sealingregion alone in order to prevent short circuit inside and the like ofthe display device as shown in FIG. 5(B). Moreover, as shown in FIG. 4,the blocking effect on contaminated materials is further improved when alaminated sealing film is used for blocking the contaminated materials,compared to that of the case of using a single layer sealing film. FIG.21 shows an example of using a film lamination structure of a filmincluding the same material as that of a wiring and a film including thesame material as that of an ITO as a sealing film. In FIG. 21, referencenumeral 9500 denotes a sealing region; 9501, a peripheral circuitportion; 9502, a pixel portion; 9503 and 9506, p-channel type TFTs; 9504and 9505, n-channel type TFTs; 2100, substrate; 2101, a wiring; 2111 and2114, electrodes (anode or cathode), 2112, a bank; 2113, alight-emitting layer; 2115, a light-emitting element; 2118, an opening,2119 a and 2119 b, a sealing film (protective film) covering the opening2118 and side edge part; and 2117, a sealing agent.

Moreover, a display device with high reliability can be manufacturedwithout increasing the manufacturing steps even though films forming thedisplay device are used as a sealing film by any combination. However,the sealing film formed at outermost side to be exposed to theatmosphere including external moisture and moisture is required to havea dense structure which can block the moisture and oxygen. Although asealing agent is formed in a part of the sealing film in FIGS. 20 and21, it may be formed so as to cover the entire sealing film.

A display device having a conventional structure and a display devicehaving a structure using the present embodiment are evaluated in theirreliability. Here, a sealing film including the same material as that ofa wiring is used employing the structure of Embodiment Mode 1.

In the reliability evaluation, change in luminance is examined bystoring the display device at a temperature of 65° C., a humidity of 95%for 190 hours. FIG. 15 shows a light emission of the display devicehaving a conventional structure, and FIG. 16 shows a light emission ofthe display device having a structure using the present embodiment. Eachof the display devices are examined after being stored for 190 hoursunder the conditions above. Pictures in FIG. 15 and FIG. 16 show lightemission of nine parts emitting a light respectively in a pixel region.FIGS. 15 and 16 respectively show light-emission after being stored for190 hours under the conditions above of a display device having aconventional structure and a display device having a structure using thepresent embodiment.

As is apparent from FIG. 15, according to the display device having theconventional structure, nonluminescent region is spread from the endpart of the display device to a center part. The phenomenon above is adegradation called shrink due to that contaminated materials such asmoisture and oxygen enter the inner part of the display device. Comparedto that, such degradation is hardly found in FIG. 16. This inventionimplies that the contaminated materials such as moisture and oxygen areshut off and cannot enter the inner part of the display device.

As for the display device having the structure according to the presentembodiment, a film such as an interlayer film is no longer exposeddirectly to the atmosphere in the outside of the display device.Therefore, it becomes possible to prevent moisture and oxygen outside ofthe display device from entering though interspace between films intoinner part of the display device. Accordingly, various degradations suchas contamination of an inner part of the display device, the degradationof electric properties, a dark spot and shrink which are caused bymoisture and oxygen can be prevented to make improvement in reliabilityof the display device possible. Moreover, in the present invention, adisplay device with high reliability can be manufactured withoutincreasing the manufacturing steps because a film using the samematerial as that of a film which forms the display device is used for asealing film.

A display device manufactured like this manner has a structure shuttingcontaminated materials off in a sealing region at an end part of thedisplay device. Therefore, the operating characteristics and thereliability of the display device becomes sufficient. In addition, suchdisplay device can be used as a display unit of various electronicsdevices.

[Embodiment 3]

Referring FIG. 10, the present embodiment describes an example of adisplay device manufactured in embodiment 2, which has a differentstructure of a sealing film. Therefore, a part having the similarstructure to that of Embodiment 2 may be manufactured by the method ofEmbodiment 2.

Also in the present embodiment, as Embodiment 2, a display device ismanufactured by using a method for manufacturing a TFT in forming anactive matrix substrate which is shown in Embodiment 1.

FIG. 10 is a cross-sectional view showing a display device of thepresent embodiment. In FIG. 10, reference numeral 5000 denotes a sealingregion; 5001, a peripheral driving circuit; 5002, a pixel portion; 5003and 5006, p-channel type TFTs; 5004 and 5005, n-channel type TFTs; 1000,a substrate; 1001, a wiring; 1011 and 1014, electrodes (anode orcathode); 1012, a bank; 1013, a light-emitting layer; 1015, alight-emitting element; 1018, an opening; 1019, a sealing film(protective film) covering the opening 1018 and the side end part; and1017, a sealing agent.

In the present embodiment, the electrode 1011 includes a transparentconductive film. As the transparent conductive film, a compound ofindium oxide and tin oxide, a compound of indium oxide and zinc oxide, azinc oxide, a tin oxide and an indium oxide can be used. Further, a filmformed by adding gallium to the transparent conductive film may be used.

As shown in FIG. 10, a film including the same material as that of theelectrode 1011 may be formed on a source electrode and a drain electrodeas a sealing film when the electrode 1011 is formed. Nonphotosensitiveacrylic, photosensitive acrylic and an inorganic material can be usedfor an interlayer insulating film below the source electrode and thedrain electrode. Dry etching is required in opening a contact on theinterlayer film including a nonphotosensitive acrylic and inorganicmaterial. A protrusion and depression are formed on an etched crosssection by dry etching, which is likely to degrade film formation of thesource and drain electrodes. By forming the sealing film on the sourceand drain electrodes as shown in FIG. 10, moisture and oxygen isprevented from entering from a disconnecting part (hole on a film). Thedisconnecting part is likely to be caused by the inferior film formationof the source electrode and the drain electrode. Accordingly, thedegradation due to moisture and oxygen of an EL display device can beprevented.

The electrode 1014 including a conductive film is formed on thelight-emitting layer 1013. In the case of the present invention, analloy of aluminum and lithium is used as the conductive film. Of course,a well-known MgAg film (alloy film of magnesium and silver) may be used.As a cathode material, a conductive film including a Group 1 element orGroup 2 element of periodic table, or a conductive film in which thoseelements are added may be used.

In the present embodiment, the sealing film 1019 is formed from the samematerial as that of the electrode 1014 in forming a cathode which isformed on the light-emitting layer 1013. The opening 1018 reaching up tothe substrate is formed, and the sealing film 1019 then formed so as tocover the opening. A conductive film having a function of a cathode anda sealing film is formed continuously up to outside of a peripheralcircuit to protect the EL element and the TFT inside. Accordingly, whenmoisture and oxygen enter through the interlayer film such as acrylicwhich is exposed to the external atmosphere, those moisture and oxygencan be shut off by the sealing film of the present invention. Therefore,the degradation of an EL display device due to moisture and oxygen canbe prevented. Moreover, the electrode 1014 and the sealing film 1019 maybe connected each other, and may also be formed separately by using amask and the like.

In the present invention, although a film including the same material asthat of a cathode is used, a passivation film may be formed on thecathode (a second electrode) to form the sealing film by the same stepsand with the same material as those of the passivation film.

The present embodiment can be combined with Embodiment Mode 1 or 2, orany one of Embodiments 1 to 3, or the present embodiment can also becombined with plural from the embodiment modes and the embodimentsabove.

[Embodiment 4]

Referring FIG. 18, the present embodiment describes an example of thedisplay device manufactured in Embodiment 2 or 3, each of which has adifferent connecting structure of a pixel electrode with a source anddrain electrodes and a different structure of a sealing film. In FIG.18, reference numeral 8000 denotes a sealing region; 8001, a peripheralcircuit portion; 8002, a pixel portion; 8003 and 8006, p-channel typeTFTs; 8004 and 8005, n-channel type TFTs; 1100, a substrate; 1101, awiring; 1111 and 1114, electrodes (anode and cathode); 1112, a levelinglayer; 1131, a light-emitting layer; 1115, a light-emitting element;1116, a bank; 1118, an opening; 1119, a sealing film (protective film)covering the opening 1118 and side edge part; and 1117, a sealing agent.

As shown in FIG. 18, the leveling layer 1112 is formed on the wiring1101 serving as a source and drain electrodes to provide the electrode1111 thereon. At this time, the leveling layer 1112 may be an inorganicinsulating film or an organic insulating film. It is effective to usethe leveling film for further improvement on flatness. Nonphotosensitiveacrylic, photosensitive acrylic, an inorganic material and the like canbe used for the leveling layer 1112. In addition, a material in which askeletal structure is formed by bonding of silicon and oxygen may beused. As the material in which a skeletal structure is formed by thebonding of silicon and oxygen, siloxanic polymer is cited as a typicalexample. Specifically, it is a material wherein a skeletal structure isformed by the bonding of silicon and oxygen and wherein a substituentincludes at least hydrogen, or a material wherein a substituent includesat least one from the group consisting of fluorine, alkyl and aromatichydrocarbon.

It is effective to flatten the steps due to a TFT by using a levelingfilm. Insufficient emitting due to the steps is likely to occur becausethe light-emitting layer formed later is very thin. Therefore, it ispreferable to form a leveling film before forming the pixel electrode inorder to form a light-emitting layer on a flat plane as far as possible.

The electrode 1114 including a conductive film is provided on thelight-emitting layer 1113. In the present embodiment, an alloy ofaluminum and lithium is used as the conductive film. Of course awell-known MgAg film (an alloy film of magnesium and silver) may beused. As a cathode material, a conductive film including a Group 1element or Group 2 element of the periodic table, or a conductive filmin which those elements are added may be used.

In the present embodiment, the sealing film 1119 is formed of the samematerial as that of the electrode 1114 in forming the electrode 1114provided on the light-emitting layer. The opening 1118 reaching up tothe substrate is formed, and the sealing film 1119 is formed so as tocover the opening. A conductive film having a function of a cathode anda sealing film is formed continuously up to outside of a peripheralcircuit to cover inside EL element and TFT. Accordingly, even thoughmoisture and oxygen enter through an interlayer film such as acrylicwhich is exposed to the external atmosphere, the moisture and oxygen canbe shut off by the sealing film of the present invention. Therefore, thedegradation due to moisture and oxygen of an EL display device can beprevented. Moreover, the electrode 1114 and the sealing film 1119 may beconnected each other, and may also be formed separately by using a maskand the like.

In the present invention, although a film formed of the same material asthat of a cathode is used as a sealing film, a passivation film may beformed on the cathode (a second electrode) to form the sealing film bythe same steps and with the same material as those of the passivationfilm.

In the case of using acrylic and the like with hygroscopic property, theleveling film is likely to become a path for moisture at a place such asa peripheral circuit that is not to be flattened. Therefore, it also iseffective to remove the leveling layer. However, in order to preventdamage on a film such as plasma due to dry etching and the like inremoving the leveling film, an outer end part of the insulating layermay be covered with a sealing film including the same material as thatof the electrode and the passivation film as described in EmbodimentMode 1 in the case of not removing the leveling layer.

In the present embodiment, although the sealing structure is used in thecase of an EL display device, the sealing structure of the presentinvention is applicable to a liquid crystal display device having thestructure using Embodiment 1 and the leveling film of the presentembodiment. In that case, a display device using not a light-emittingelement but a crystal for a display unit may be manufactured.

The present embodiment can be combined with Embodiment Mode 1 or 2, orany one of Embodiments 1 to 3, or the present embodiment can also becombined with plural from the embodiment modes and the embodimentsabove.

[Embodiment 5]

Various display devices (active matrix type display device) can bemanufactured by applying the present invention. That is, the presentinvention is applicable to various electric equipment incorporatingthose display devices into the display unit.

As those electric equipment, a video camera, a digital camera, aprojector, a head mount display (goggle-type display), a car navigation,a car stereo, a personal computer, a personal digital assistant (mobilecomputer, cell phone, electric book and the like) and the like arecited. FIGS. 12, 13 and 14 show an example of those.

FIG. 12(A) shows a personal computer, which includes a body 3001, animage inputting unit 3002, a display unit 3003, a keyboard 3004 and thelike. A personal computer of the present invention is completed byapplying a display device manufactured according to the presentinvention to the display unit 3003.

FIG. 12(B) shows a video camera, which includes a body 3101, a displayunit 3102, an audio inputting unit 3103, an operating switches 3104, abattery 3105, a image receiving unit 3106 and the like. A video cameraof the present invention is completed by applying a display devicemanufactured according to the present invention to the display unit3102.

FIG. 12(C) shows a mobile computer, which includes a body 3201, a cameraunit 3202, an image receiving unit 3203, an operating switch 3204, adisplay unit 3205 and the like. A mobile computer of the presentinvention is completed by applying a display device manufacturedaccording to the present invention to the display unit 3205.

FIG. 12(D) shows a goggle-type display, which includes a body 3301, adisplay unit 3302, an arm unit 3303 and the like. In the display unit3302, a flexible substrate is used as a substrate in order tomanufacture the goggle-type display curving the display units 3302. Inaddition, a light and thin goggle-type display is realized. Thegoggle-type display of the present invention is completed by applying adisplay device manufactured according to the present invention to thedisplay unit 3302.

FIG. 12(E) shows a player using a recording medium recording a program(hereinafter referred to as the recording medium), which includes a body3401, a display unit 3402, a speaker unit 3403, a recording medium 3404,an operating switch 3405 and the like. Here, the player makes itpossible to appreciate music and a movie, play a game and surf on theinternet by using a DVD (Digital Versatile Disc), CD and the like as therecording medium. The recording medium of the present invention iscompleted by applying a display device manufactured according to thepresent invention to the display unit 3402.

FIG. 12(F) shows a digital camera, which includes a body 3501, a displayunit 3502, a view finder 3503, an operating switches 3504, an imagereceiving unit (not shown in the figure) and the like. The digitalcamera of the present invention is completed by applying a displaydevice manufactured according the present invention to the display unit3502.

FIG. 13(A) shows a front type projector, which includes a projectionunit 3601, a screen 3602 and the like. A front type projector iscompleted by applying a display device manufactured according to thepresent invention to a liquid crystal display device 3808 forming a partof the projection unit 3601 and to other driving circuits.

FIG. 13(B) shows a rear type projector, which includes a body 3701, aprojection unit 3702, a mirror 3703, a screen 3704 and the like. A reartype projector is completed by applying a display device that ismanufactured according to the present invention to the liquid crystaldisplay device 3808 forming a part of the projection unit 3702 and toother driving circuit.

FIG. 13(C) shows an example of a structure of the projection units 3601and 3702 that are shown in FIGS. 13(A) and 13(B), respectively. Each ofthe projection units 3601 and 3702 is comprised of a light sourceoptical system 3801, mirrors 3802 and 3804 to 3806, dichroic mirrors3803, a prism 3807, a liquid crystal display device 3808, phasedifference plates 3809, and a projection optical system 3810. Theprojection optical system 3810 includes an optical system includingprojection lenses. The present embodiment shows an example of athree-plate system, but there are no special limitations. For instance,an optical system of single plate system is acceptable. Further, theoperator may suitably set optical systems such as optical lenses, apolarizing film, a film to regulate the phase difference, an IR film,within an optical path shown by the arrows in FIG. 13(C).

In addition, FIG. 13(D) shows an example of a structure of the lightsource optical system 3801 in FIG. 13(C). In the present embodiment, thelight source optical system 3801 is composed of a reflector 3811, alight source 3812, lens arrays 3813 and 3814, a polarizing conversionelement 3815, and a condenser lens 3816. Note that the light sourceoptical system shown in FIG. 13(D) is an example, and there is nolimitation specifically. For example, the operator may suitably setoptical systems such as optical lenses, a polarizing film, a film toregulate the phase difference, and an IR film.

Here, the projector shown by FIGS. 13 shows the case of using atransparent electro-optic device, an example of application to areflective electro-optic device and display device are not shown in thefigure.

FIG. 14(A) shows a cell phone, which includes a body 3901, an audiooutputting unit 3902, an audio inputting unit 3903, a display unit 3904,an operating switches 3905, an antenna 3906 and the like. A cell phoneof the present invention is completed by applying a display devicemanufactured according to the present invention to the display unit3904.

FIG. 14(B) shows a mobile book (electric book), which includes a body4001, display units 4002 and 4003, a storage medium 4004, an operatingswitch 4005, an antenna 4006 and the like. A mobile book of the presentinvention is completed by applying the display device of the presentinvention to the display units 4002 and 4003.

FIG. 14(C) shows a display, which includes a body 4101, a support table4102, a display unit 4103 and the like. The display unit 4103 ismanufactured by using a flexible substrate, thereby realizing a lightand thin display. In addition, it is possible to curve the display unit4103. A display of the present invention is completed by applying thedisplay device manufactured according to the present invention to thedisplay unit 4103.

As described above, the application of the present invention isextremely wide, and the present invention is applicable to electricequipment in various fields.

[Embodiment 6]

Referring to FIGS. 20 and 21, the present embodiment describes anexample of a display device manufactured in Embodiment 2 or 3, each ofwhich has a different structure of a sealing film.

In FIG. 20, reference numeral 2000 denotes a substrate; 2001, a wiring;2011, an electrode (anode or cathode); 2013, a light-emitting layer;2014, an electrode (anode or cathode), 2115; a light-emitting element;and 2017, a sealing agent. In FIG. 20, the sealing film 2019 is formedby the same steps and with the same material as those of the wiring2001. FIG. 20 shows the structure in which the opening 2018 reaching upto the substrate 2000 is formed, and in which the sealing film 2019covers the opening 2018, and a bare part of an insulating layer at anend part of the display device.

In FIG. 21, reference numeral 2100 denotes a substrate; 2101, a wiring;2111, an electrode (anode or cathode); 2013, a light-emitting layer;2114, an electrode (anode or cathode); 2115, a light-emitting element;and 2117, a sealing agent. In FIG. 21, a sealing film 2119 a formed fromthe same material as that of the wiring 2101 and a sealing film 2119 bformed from the same material as that of the pixel electrode 2111 areused. The sealing films 2119 a and 2119 b are formed by the same stepsas that of the wiring 2101 and the pixel electrode 2111 at the sametime, respectively. The opening 2118 reaching up to the substrate 2100is formed in the sealing region so as to be covered with the sealingfilms 2119 a and 2119 b, and those sealing films covers a bare part ofan insulating layer at an end part of the display device.

In the present embodiment, although the opening 2118 in the sealingregion is formed so as to reach up to the substrate, it is acceptablethat the sealing film reaches only to dense base film. It is enough ifan opening is formed on a hydrophilic film to be a path for moisture.Therefore, a depth of the opening may be suitably set. The presentembodiment is an example of the present invention, and the presentinvention is not limited to the present embodiment.

According to the present invention, moisture and oxygen are shut off bya sealing film even though the moisture and the oxygen enters through aninterlayer film and a leveling layer 2012 such as acrylic exposed to asealing agent and the external atmosphere. Therefore, an EL element anda TFT inside of the display device can be protected. Accordingly, thedegradation due to moisture and oxygen of the EL display device can beprevented. In addition, when the plural sealing films are stacked asshown in FIG. 21, capability of shutting off contaminated materials suchas moisture is further improved.

A display device of the present invention is manufactured to beevaluated in its reliability. In the reliability evaluation, change inluminance is examined by storing the display device at a temperature of65° C., a humidity of 95% for approximately 500 hours. FIG. 23 showslight emission of a display device having the structure of FIG. 20, andFIG. 24 shows a display device having the structure of FIG. 21. Each ofthe display devices after being stored for 500 hours under theconditions above is shown. Pictures in FIGS. 23 and 24 show lightemission of nine parts emitting a light respectively in a pixel region.

In the display device in which an EL element and a TFT is protected, aluminance degradation begins a little from upper-right corner andlower-left corner, however, a serious degradation is not found. Inaddition, a display device in which the sealing film is stacked to forma lamination layer structure in FIG. 24, such degradation is hardlyfounded. This implies that moisture are shut off several times andcannot enter inside of the display device by covering an opening and endpart with the sealing film. Moreover, by stacking plural sealing filmsto the lamination layer, blocking capability is found to be improved andthe degradation of the display device can be prevented.

According to the display device of the present invention, a film such asan interlayer film is no longer to be exposed to external atmosphere.Therefore, it becomes possible to prevent moisture and oxygen outside ofthe display device from entering the display device through theinterlayer film and the interspace between films. Accordingly, thereliability of the display device can be enhanced by preventing variousdegradations caused by moisture and oxygen such as contamination of aninner part of the display device, the degradation of electricproperties, a dark spot and shrink. Moreover, in the present invention,a display device with high reliability can be manufactured withoutincreasing the manufacturing steps because a film using the samematerial as that of a film which forms the display device is used for asealing film.

[Embodiment 7]

The present embodiment shows display devices each having differentwiring arrangement drawn into an end part of the display device withreference to FIGS. 1, 19, 22 and 25.

In FIG. 1, the wiring of a pixel portion is connected to an FPC(flexible print circuit) in the region 411. FIG. 19 shows an enlargedview of the region 411. FIG. 19 shows a conventional wiring arrangement.Reference numeral 1901 denotes a cathode; 1902, a first anode; 1903, asecond anode; and 1904, a third anode. In the conventional arrangement,the cathode 1901 serving as a wiring of outermost circumference connectsto an FPC at innermost. Accordingly, the end part of the display devicecannot be covered with a wiring at the outermost circumference.Therefore, moisture and the like enter the display device and thedegradation of the display device is not prevented.

FIG. 22 is a view showing wiring arrangement of a display deviceaccording to the present invention. The first anode 1902 connecting toan FPC at outermost of the display device is arranged outermost.Therefore, it becomes possible that the wiring of the outermostcircumference covers an end part of the display device completelywithout any interspace, and moisture can be shut off sufficiently.

As for the arrangement of the wiring, it is enough if an outermostcircumference wiring connects other wiring such as an FPC on theoutermost side; therefore, the kind, polarity and number of the wiringmay be suitably set.

A display device having the wiring arrangement of FIG. 22 and thestructure of FIG. 20 is manufactured and evaluated in its reliability.In the reliability evaluation, change in luminance is examined bystoring the display device at a temperature of 65° C., a humidity of 95%for approximately 570 hours. FIG. 25 shows a light emission of thedisplay device having structures of FIGS. 20 and 22 after being storedfor 500 hours under the conditions above.

As shown in FIG. 25, although the luminance degradation called shrink isappeared a little on upper and lower left side, the display device ishardly degraded. In addition, the degree of the degradation is a bitlighter compared to the conventional display device shown in FIG. 23having the wiring arrangement of FIG. 19. Therefore, according to thepresent invention, it is found that the effect of preventing a displaydevice from degradation is enhanced.

According to the structure of the present invention, it becomes possibleto prevent various degradations caused by moisture and oxygen such ascontamination of an inner part of the display device, the degradation ofelectric properties, a dark spot and shrink, therefore, the reliabilityof the display device is enhanced.

1. A display device comprising: a pair of substrates; a base film formedon either one surface of the substrates; an insulating film formed overthe base film; a display unit formed over the insulating film; alight-emitting element formed in the display unit; a sealing film formedover the display unit; and a sealing agent formed outside of the displayunit so as to surround a periphery of the display unit, wherein the pairof substrates are attached to each other by the sealing agent, whereinat least one layer of the insulating film is formed from an organicresin material, wherein the insulating film has an opening to be coveredwith the sealing film, wherein the base film is in contact with thesealing film in the opening, and wherein the sealing agent is formedadjoining to the sealing film.
 2. A display device comprising: a pair ofsubstrates; a base film formed on either one surface of the substrates;an insulating film formed over the base film; a display unit formed overthe insulating film; a light-emitting element formed in the displayunit; a sealing film formed over the display unit; and a sealing agentformed outside of the display unit so as to surround a periphery of thedisplay unit, wherein the pair of substrates are attached to each otherby the sealing agent, wherein at least one layer of the insulating filmis formed from an organic resin material, wherein the insulating filmhas an opening to be covered with the sealing film, wherein the basefilm is in contact with the sealing film in the opening, and wherein anouter end part of the base film located outside of the sealing agent isin contact with the sealing film.
 3. A display device comprising: a pairof substrates; a base film formed on either one surface of thesubstrates; an insulating film formed over the base film; a display unitformed over the insulating film; a light-emitting element formed in thedisplay unit; a sealing film formed over the display unit; and a sealingagent formed outside of the display unit so as to surround a peripheryof the display unit, wherein the pair of substrates are attached to eachother by the sealing agent, wheiein at least one layer of the insulatingfilm is formed from an organic resin material, wherein the insulatingfilm has plural openings to be covered with the sealing film, whereinthe base film is in contact with the sealing film in the pluralopenings, and wherein the sealing agent is formed adjoining to thesealing film.
 4. A display device comprising: a pair of substrates; abase film formed on either one surface of the substrates; an insulatingfilm formed over the base film; a display unit formed over theinsulating film; a light-emitting element formed in the display unit; asealing film formed over the display unit; and a sealing agent formedoutside of the display unit so as to surround a periphery of the displayunit, wherein the pair of substrates are attached to each other by thesealing agent, wherein at least one layer of the insulating film isformed from an organic resin material, wherein the insulating film hasplural openings to be covered with the sealing film, wherein the basefilm is in contact with the sealing film in the plural openings, andwherein an outer end part of the base film located outside of thesealing agent is in contact with the sealing film.
 5. A display deviceaccording to claim 1, wherein the sealing film includes one or pluralkinds of films selected from a group consisting of a conductive thinfilm and an insulating thin film.
 6. A display device according to claim1, wherein the sealing film includes one or plural kinds of elementsselected from a group consisting of Al, Ti, Mo, W and Si.
 7. A displaydevice according to claim 1, wherein the sealing film includes one orplural kinds of films selected from a group consisting of a siliconnitride film, a silicon nitride oxide film or a nitrogen-containingcarbon film.
 8. A display device according to claim 1, wherein theorganic resin material includes one or plural kinds of materialsselected from a group consisting of silicon oxide including acrylic,polyamide and polyimide.
 9. A display device according to claim 2,wherein the sealing film includes one or plural kinds of films selectedfrom a group consisting of a conductive thin film and an insulating thinfilm.
 10. A display device according to claim 2, wherein the sealingfilm includes one or plural kinds of elements selected from a groupconsisting of Al, Ti, Mo, W and Si.
 11. A display device according toclaim 2, wherein the sealing film includes one or plural kinds of filmsselected from a group consisting of a silicon nitride film, a siliconnitride oxide film or a nitrogen-containing carbon film.
 12. A displaydevice according to claim 2, wherein the organic resin material includesone or plural kinds of materials selected from a group consisting ofsilicon oxide including acrylic, polyamide and polyimide.
 13. A displaydevice according to claim 3, wherein the sealing film includes one orplural kinds of films selected from a group consisting of a conductivethin film and an insulating thin film.
 14. A display device according toclaim 3, wherein the sealing film includes one or plural kinds ofelements selected from a group consisting of Al, Ti, Mo, W and Si.
 15. Adisplay device according to claim 3, wherein the sealing film includesone or plural kinds of films selected from a group consisting of asilicon nitride film, a silicon nitride oxide film or anitrogen-containing carbon film.
 16. A display device according to claim3, wherein the organic resin material includes one or plural kinds ofmaterials selected from a group consisting of silicon oxide includingacrylic, polyamide and polyimide.
 17. A display device according toclaim 4, wherein the sealing film includes one or plural kinds of filmsselected from a group consisting of a conductive thin film and aninsulating thin film.
 18. A display device according to claim 4, whereinthe sealing film includes one or plural kinds of elements selected froma group consisting of Al, Ti, Mo, W and Si.
 19. A display deviceaccording to claim 4, wherein the sealing film includes one or pluralkinds of films selected from a group consisting of a silicon nitridefilm, a silicon nitride oxide film or a nitrogen-containing carbon film.20. A display device according to claim 4, wherein the organic resinmaterial includes one or plural kinds of materials selected from a groupconsisting of silicon oxide including acrylic, polyamide and polyimide.